Development of new formulation for smart sunscreen

Sun exposure has several health benefits; however, awareness and caution are recommended by using sunscreen to counter photo-aging and photo-carcinogenesis processes. Nanoparticles (NPs), in recent years, have been widely used in cosmetology with different purpose such their antibacterial activity or their capability in reflecting the ultraviolet radiation (UVR). Inorganic nanosized filters such titania dioxide (TiO2) and zinc oxide (ZnO) are increasingly in use in sunscreen formulations since they can be easily incorporated into emulsions, they appeare transparent to visible radiation and reflection from the particle surface is minimal. In light of this the first part of this thesis work was focused on the synthesis of ZnO NPs obtained through a green approach. The Vitis vinifera rubra leaf extract was used as capping agent, the purpose was to make ZnO NPs safer to be inserted into an emulsion formulation for topical application, and at the same time valorise an agri-food waste biomass coming from the territory. The obtained materials were characherized via trasmission electron microscopy (TEM), scansion electron microscopy (SEM), physisorption and FTIR spectroscopy. Afterwards the effectiveness of the optimized ZnO NPs was evaluated trought their integration in a formulation coming from a green matrix too, preaviusly developed in the laboratory were I have conducted my internship, in order to obtain a mineral sunscreen. The emulsion was subjected to an ex vivo release test with the support of Franz’s vertical diffusion cell, microbiological analysis and SPF evaluation. Several stress tests and reological analysis were also performed to investigate the stability of the finished product.